Dedicated tdls link in off-channel 5 ghz band using rsdb

ABSTRACT

Devices, systems and methods establish a first wireless link with an access point (AP) via a first frequency band, establish a tunneled direct link setup (TDLS) link with a peer wireless device using the first frequency band. Embodiments, switch from using the first frequency band for the TDLS link to using a second frequency band for the TDLS link and use a real-time simultaneous dual band (RSDB) configuration to communicate with the peer wireless device through the TDLS link using the second frequency band and concurrently communicate with the AP through the first wireless link using the first frequency band.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/710,328, filed on Dec. 11, 2019, which is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

The subject technology generally relates to wireless communicationsystems, and more particularly, to methods and systems for a wirelessdevice to perform real time simultaneous communication with multiplesdevices using two different frequency bands or channels of a wirelesscommunication medium.

BACKGROUND

WLAN systems complying with the IEEE 802.11 (WiFi™) standard are used bya wide array of devices for multimedia and gaming applications. The WiFistandard and a host of other standards such as Bluetooth™ use channelsin the 2.4 GHz industrial, scientific and medical (ISM) frequency band.Even when a device is dual-band capable, such as a mobile device that iscapable of working in both the 2.4 GHz and 5 GHz bands, the device maychoose to operate in the crowded 2.4 GHz band over the 5 GHz band basedon higher received signal strength indicator (RSSI) or easierdiscoverability due to better signal propagation characteristics of 2.4GHz signals compared to 5 GHz signals when the device associates with adual-band access point (AP). To reduce the congestion in the 2.4 GHzband, an amendment of the IEEE 802.11z standard provides the facilityfor mobile devices, also referred to as stations or STAs, that aredual-band capable and connected to a traditional WiFi network in the 2.4GHz band, to establish a direct link with other peer STAs in the 5 GHzband using tunneled direct link setup (TDLS). The dual-band capable STAmay communicate with its associated AP over the 2.4 GHz band, alsoreferred to as the base-channel, while using the 5 GHz band, alsoreferred as the off-channel, for TDLS direct links with one or more peerSTAs. Conventionally, the STA working in such virtual simultaneous dualband (VSDB) configuration with the TDLS direct links toggles between theoff-channel and the base-channel. For example, the STA operating withthe TDLS direct link may periodically put the off-channel in the powersaving mode and may switch from the off-channel to the base-channel toreceive beacons and communicate with legacy STAs via the AP over thebase-channel. After operating in the base-channel, the STA may put thebase-channel in the power saving mode and may switch back to theoff-channel to transfer data over the TDLS direct links with other peerSTAs. However, switching between the off-channel and base channelintroduces latency in the TDLS direct links, making the VSDBconfiguration with TDLS direct links less than ideal for supportinggaming and multimedia applications that require low latency and seamlessdata transfer.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments and the advantages thereof may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings. These drawings in no waylimit any changes in form and detail that may be made to the describedembodiments by one skilled in the art without departing from the spiritand scope of the described embodiments.

FIG. 1 illustrates an example of a WLAN system in which two wirelessdevices (STAs) communicate with an access point (AP) of a WiFi networkover the base-channel, in accordance with one embodiment of the presentdisclosure.

FIG. 2 illustrates an example of two STAs communicating with the AP overthe base-channel and communicating with one another via a TDLS directlink over the off-channel using a real time simultaneous dual band(RSDB) configuration in accordance with one embodiment of the presentdisclosure.

FIG. 3 illustrates an example of three STAs communicating with the APover the base-channel and one of the STAs communicating with the twoother STAs via two TDLS direct links over the off-channel using the RSDBconfiguration in accordance with one embodiment of the presentdisclosure.

FIG. 4 shows a flow chart of a method for an initiator STA to establisha connection with an AP over the base-channel for communicating with theAP and legacy STAs and to establish a TDLS direct link with a peer STAover the off-channel in the RSDB configuration in accordance with oneembodiment of the present disclosure.

FIG. 5 is a block diagram of a dual-band radio device of a STA thatsupports RSDB communication over the base-channel with an AP and overthe off-channel with peer STAs using TDLS direct links in accordancewith one embodiment of the present disclosure.

FIG. 6 is a block diagram of a dual-band WLAN device of a STA thatsupports RSDB communication over the base-channel with an AP and overthe off-channel with peer STAs using TDLS direct links in accordancewith one embodiment of the present disclosure.

DETAILED DESCRIPTION

Examples of various aspects and variations of the subject technology aredescribed herein and illustrated in the accompanying drawings. Thefollowing description is not intended to limit the invention to theseembodiments, but rather to enable a person skilled in the art to makeand use this invention. For example, while examples, implementations,and embodiments of the subject technology are described using wirelessdevices operating in a WLAN system that complies with various versionsof the IEEE 802.11 (WiFi™) standard, the subject technology is not thuslimited and may be applicable to other types of communication devicesoperating in other types of WLAN systems or in a wide area network.

To make full use of TDLS direct links with peer STAs in a dual-bandcapable STA of a WiFi system, it is desirable for the STA to operate ina real-time simultaneous dual band (RSDB) configuration in which thebase-channel link to the WiFi network through the AP and the off-channellinks to the peer STAs through the TDLS may operate in parallel. Forexample, the STA may operate the base-channel link over the 2.4 GHz bandto receive beacons from the AP and to communicate with legacy STAs inparallel with operating the off-channel TDLS direct links over the 5 GHzband to communicate with peer STAs. In contrast to a virtualsimultaneous dual band (VSDB) configuration, the STA does not need totoggle between the base-channel and the off-channel to operate bothlinks. That is, in the RSDB configuration the STA does not need to putthe base-channel link in the power saving mode to communicate with thepeer STAs over the TDLS links using the off-channel. Similarly, the STAdoes not need to put the off-channel TDLS links in the power saving modeto communicate with legacy STAs via the AP over the base-channel.

Advantageously, by avoiding switching between the base-channel and theoff-channel, the RSDB configuration enables low latency data transferover the direct TDLS links. Discontinuity of data transfer over thedirect TDLS links may also be eliminated. When there are multiple TDLSlinks to multiple peer STAs, the improvement in data throughput isfurther enhanced due to the elimination of more switching opportunities.The TDLS links for peer-to-peer communication in the RSDB configurationmay thus support the requirements for low latency and seamless datatransfer of gaming and multimedia applications. In addition, thebase-channel is always available for data transfer with legacy STAs inthe WiFi network, improving latency and data throughput with the legacySTAs as well.

A STA that supports RSDB may have a dual-band radio transceiver thatcontains two media access controllers (MACs) and two physical layercores (PHYs). A first pair of MAC and PHY may to operate over the 2.4GHz base-channel with an AP to transfer data with legacy STAs thatoperate in the 2.4 GHz band. A second pair of MAC and PHY may beconfigured to operate over the 5 GHz off-channel to transfer data on oneof more TDLS direct links with one or more peer STAs. While theoff-channel is characterized as the 5 GHz band in various embodimentsdescribed, it is understood that the off-channel may include otherfrequency bands such as 6 GHz, 7 GHz bands or sub-GHz bands. The firstpair of MAC and PHY may only support 2.4 GHz operation. The second pairof MAC and PHY may be capable of supporting both the 2.4 GHz band andthe 5 GHz band but is configured for the 5 GHz operation for the TDLSdirect links. Each respective pair of MAC and PHY may transmit andreceive over one or more antennas. By having two pairs of MAC and PHYthat operate independently over the 2.4 GHz and the 5 GHz bands, the STAmay maintain the base-channel link and the off-channel TDLS links inparallel for RSDB operation.

To perform RSDB operation, the STA may initially discover and associatewith an AP over the 2.4 GHz band to establish a link with the AP overthe base-channel. The AP with the associated STA and other STA similarlylinked and managed by the AP may constitute a basic service set (BSS) ofthe WiFi network. The STA may use the pair of MAC and PHY that operatesonly over the 2.4 GHz band, which may be referred to as transceiver-1,to establish the link with the AP. The other pair of MAC and PHY, whichmay be configured to operate over the 5 GHz band and may be referred toas transceiver-0, may be in the power saving mode initially. In oneembodiment, to achieve better antenna gain or for antenna diversity, theSTA may configure transceiver-1 to transmit and receive over the antennaof transceiver-1 and the antenna of transceiver-0 in amultiple-in-multiple-out (MIMO) configuration. To setup a TDLS link withpeer STAs that are also associated with the AP, the STA and the peerSTAs may exchange their device capabilities. For example, the STA maytransmit a TDLS setup request frame via the AP to advertise itsoff-channel capability and to inquire about the off-channel capabilitiesof peer STAs. If a peer STA is dual-band capable, the peer STA mayrespond with a TDLS response frame indicating that it supportsoff-channel capability. The TDLS response frame may also contain a TDLSchannel switching capability field that indicates that the peer STA iscapable of RSDB operation using the off-channel TDLS link.

The STA may initially establish a TDLS link with the peer STA over thebase channel if the peer STA supports off-channel operation. Upon thesuccessful establishment of the TDLS link and if the peer STA's TDLSchannel switching capability field is set, the STA may initiate achannel switch request for the 5 GHz off-channel. For example, the STAmay transmit a TDLS channel switch request frame over the TDLS directlink in the base channel to the peer STA. The peer STA may respond witha TDLS channel switch response frame over the TDLS direct link in thebase channel to the STA. Upon the successful channel switch negotiation,the STA and the peer STA may switch their TDLS direct link from thebase-channel to the 5 GHz off-channel. The STA may then listen fortransmission from the peer STA or transmit to the peer STA over theoff-channel TDLS direct link. For example, the STA may configure the MACand PHY of transceiver-0 for the TDLS direct link with the peer STA.Tranceiver-0 may transmit and receive over the 5 GHz band using itsantenna in a single-in-single-out (SISO) configuration. The STA maycontinue to operate transceiver-1 for the link with the AP to receivebeacons from the AP and to connect to legacy STAs that operate in the2.4 GHz band. Transceiver-1 may transmit and receive over the 2.4 GHzband using its antenna in a SISO configuration.

Thus, in the RSDB configuration, the STA operates the base-channel linkand the off-channel link simultaneously. The STA does not need to switchbetween the base-channel and the off-channel when the STA transfers datawith the legacy STAs over the base-channel and with the peer STAs overthe off-channel. Both links may be fully maintained without incurringthe performance penalties of increased latency and reduced throughputwhen the STA has to put one link to the power saving mode when servingthe other link. In one embodiment, the STA may establish multiple TDLSdirect links over the 5 GHz off-channel with multiple peer STAs. If theSTA initiates the establishment of the TDLS direct links with the peerSTAs, the STA is referred to as the initiator. As the initiator, the STAmaintains a list of peer STAs, also referred as the responders, withwhich it has established TDLS direct links. The initiator may arbitraterequests from the responders for access to the TDLS direct links. In oneembodiment, if the peer STA has moved such that peer-to-peer datatransfer over the TDLS direct link over the off-channel is not feasible,the STA may negotiate with the peer STA to switch the TDLS direct linkfrom the off-channel to the base-channel via the AP.

In one aspect of the technology, when the STA wants to disable orteardown the TDLS link, the STA may send a teardown frame to the peerSTAs. The STA may disable the TDLS links with one or more peer STAs orwith all the peer STAs. If the STA is the initiator, the STA maytransmit a teardown frame to a responder through the TDLS direct linkover the off-channel. If the responder has moved such that it is nolonger reachable via the TDLS direct link, the initiator may send theteardown frame via the AP over the base-channel. The responder mayrespond with an acknowledgement frame to the teardown frame. Theinitiator may teardown the TDLS link with the responder and may clearthe entry for the responder from the list of peer STAs.

Similarly, if the responder wants to disable the TDLS link with theinitiator, the responder may transmit a teardown frame to the initiatorthrough the TDLS direct link over the off-channel or via the AP over thebase-channel. Upon receiving the teardown frame from the responder, theinitiator may teardown the TDLS link with the responder and may clearthe entry for the responder from the list of peer STAs.

In one embodiment, if the STA as the initiator wants to disassociatefrom the AP, the STA may teardown the TDLS links with all its peer STAsbefore tearing down the link to the AP over the base-channel. The STAmay transmit the teardown frames to all its responders through the TDLSdirect links over the off-channel or via the AP over the base-channel inthe manner described. After tearing down all the TDLS links and clearingall the entries for the responders from the list of peer STAs, the STAmay teardown the link to the AP. In one embodiment, the AP may want todisassociate from BSS that includes the STA and the peer STAs. The APmay transmit a disassociation frame to the STA over the base-channellink. After receiving the disassociation frame, the STA may teardown theTDLS links with all its peer STAs in the manner described.

In one embodiment, a wireless device of a STA of a wireless network isdisclosed. The wireless device includes a dual-band radio that providesa first wireless link on a first frequency band to an AP of the wirelessnetwork and a TDLS link on a second frequency band to communicate with apeer STA of the wireless network. The first wireless link and the TDLSlink may operate in parallel using the RSDB configuration to allow theSTA to communicate in parallel with the AP on the first frequency bandand with the peer STA through the TDLS link on the second frequencyband. The wireless device may be a WLAN device that conforms to anyversion of the IEEE 802.11 (WiFi™) standard.

In one embodiment, a method for establishing a connection between adual-band STA with an AP over the base-channel for communicating withthe AP and legacy STAs and for establishing a TDLS direct link betweenthe STA with a peer STA over the off-channel in the RSDB configurationis disclosed. The method includes establishing by the dual-band STA afirst wireless link on a first frequency band (e.g., 2.4 GHzbase-channel) to the AP of a wireless network. The method also includesestablishing between the STA and the peer STA a TDLS link on the firstfrequency band and determining whether the peer STA supports RSDBconfiguration on a second frequency band (e.g. 5 GHz off-channel). Ifthe peer STA supports RSDB configuration on the second frequency band,the method further includes switching the TDLS link from the firstfrequency band to the second frequency band. The method further includesthe STA communicating with the peer STA through the TDLS link on thesecond frequency band in parallel with communicating with the AP overthe first frequency band using the RSDB configuration.

FIG. 1 illustrates an example of a WLAN system in which two wirelessdevices (STAs) communicate with an access point (AP) or group owner (GO)of a WiFi network over the base-channel, in accordance with oneembodiment of the present disclosure. The WLAN system may be any versionof the IEEE 802.11 (WiFi™) standard, including 802.11z that provides thefacility for dual-band capable STAs to establish TDLS direct links withpeer STAs in the 5 GHz band. Wireless devices 106 and 107 are userequipment, also referred to as user station (STAs), that are configuredto associate with an AP 108. In one embodiment, STAs 106 and 107 may bemultimedia devices used in automotive environments, such as mediasharing or multi-user gaming consoles in an automobile, or portablecommunication devices such as smartphones that operates over a local ora wide area network. The STAs 106, 107 and the AP 108 may form a basicservice set (BSS).

AP 108 may be configured to operate over channels of the 2.4 GHz band.In one embodiment, AP 108 may be capable of operating over both the 2.4GHz and 5 GHz bands. STAs 106 and 107 are dual-band capable STAs thatsupport RSDB. For example, the hardware of STAs 106 and 107 may have twopairs of MACs and PHYs and two antennas that may be configured tooperate simultaneously over the 2.4 GHz and the 5 GHz bands. Thesoftware or firmware of STAs 106 and 107 may support TDLS. STAs 106 and107 may discover and associate with the AP 108 over the 2.4 GHz basechannel to establish a link with the AP. Once associated with the AP108, the STAs 106 or 107 may receive beacons or commands from the AP 108and may transmit data to the AP 108, with each other, or to devices of awide area network such as the Internet via AP 108. The transmission fromAP 108 to STAs 106 or 107 may be referred to as a downlink (DL)transmission. The transmission from STAs 106 or 107 to AP 108 may bereferred to as an uplink (UL) transmission. To achieve better antennagain or for antenna diversity, STAs 106 and 107 may be configured totransmit and receive data over their respective dual antennas in a 2×2MIMO configuration. Initially, communication between STAs 106 and 107are established via the STAs' respective base-channel links with the AP.This may consume bandwidth over the crowded 2.4 GHz band. To reducecongestion, STAs 106 and 107 may establish TDLS links between them overthe 5 GHz off-channel.

To setup the TDLS links, STAs 106 and 107 may exchange their devicecapabilities. For example, STA 106 may transmit a TDLS setup requestframe via AP 108 over the base-channel to advertise its off-channelcapability to STA 107 and to inquire about the off-channel capabilitiesof STA 107. If STA 107 is dual-band capable, STA 107 may respond with aTDLS response frame back to STA 106 indicating that it supports TDLSoff-channel capability. The TDLS response frame may also contain a TDLSchannel switching capability field that indicates that STA 107 iscapable of RSDB operation using the off-channel TDLS link.

FIG. 2 illustrates an example of STAs 106 and 107 communicating with AP108 over the base-channel and communicating with one another via a TDLSdirect link over the off-channel using a RSDB configuration inaccordance with one embodiment of the present disclosure. Both STAs 106and 107 support RSDB and TDLS over the 5 GHz off-channel as indicated bythe TDLS channel switching capability field during the exchange of theirdevice capabilities. STAs 106 and 107 may initially establish a TDLSlink with each other over the base channel. Upon the successfulestablishment of the TDLS link, STAs 106 and 107 may initiate channelswitch request for the 5 GHz off-channel.

STA 106 may transmit a TDLS channel switch request frame over the TDLSlink over the base channel to STA 107. Peer STA 107 may respond with aTDLS channel switch response frame over the TDLS link in the basechannel to STA 106. Upon successful channel switch negotiation, STAs 106and 107 may switch their TDLS link from the base channel to the 5 GHzoff-channel. STAs 106 and 107 may then listen for transmission from theother STA over the off-channel TDLS direct link. STA 106 and 107 mayconfigure their antennas to transmit and receive over the off-channel 5GHz band for the TDLS direct link in a SISO configuration. Similarly,STAs 106 and 107 may configure their antennas to transmit and receiveover the on-channel 2.4 GHz band for receiving commands and beacons fromAP 108 and for communicating with legacy STAs of the BSS in a SISOconfiguration.

STAs 106 and 107 may simultaneously communicate with each other overtheir off-channel TDLS direct link and with AP 108 and legacy STAs overthe base-channel in the RSDB configuration, reducing packet latency,eliminating discontinuity of data transfer, and increasing datathroughput. In one embodiment, if STAs 106 or 107 has moved such thatthe TDLS direct link over the off-channel cannot be maintained, STAs 106and 107 may negotiate to switch their TDLS direct link from theoff-channel to the base-channel. STAs 106 or 107 may repeat thehandshaking to exchange their device capabilities with other 2.4 GHz/5GHz RSDB-capable and TDLS-supported peer STAs over the base-channel,establish TDLS links with the peer STAs over the base-channel, andnegotiate to switch the TDLS links from the base-channel to theoff-channel to establish multiple TDLS direct links with multiple peerSTAs.

In the described example in which STA 106 initiated the establishment ofthe TDLS direct link with STA 107 by transmitting a TDLS setup requestframe to STA 107, STA 106 is the initiator and STA 107 is the responder.To disable the TDLS direct link, STA 106 as the initiator may transmit ateardown frame to STA 107 over the off-channel TDLS direct link. If STA107 is not reachable via the off-channel TDLS direct link and the TDLSdirect link has been switched from the off-channel to the base-channel,STA 106 may transmit the teardown frame to STA 107 through the TDLSdirect link over the base-channel. In one embodiment, if STA 107 is notreachable via the off-channel TDLS direct link, STA 106 may transmit theteardown frame to STA 107 through the AP link over the base-channel. STA107 may respond with an acknowledgement frame to the teardown frame.After receiving the acknowledgement frame, STA 106 may teardown the TDLSlink with STA 107 and may clear the entry for STA 107 from the list ofpeer STAs maintained by STA 106. In one embodiment, STA 106 may thendisassociate from AP 108 by tearing down the base-channel AP link.

STA 107 as the responder may also request that the TDLS direct link withSTA 106 be torn down by transmitting a teardown frame to STA 106 overthe off-channel TDLS direct link, the TDLS direct link over theon-channel if the TDLS direct link has been switched from theoff-channel to the on-channel, or via the AP link over the base-channel.After receiving the teardown frame, STA 106 may teardown the TDLS linkwith STA 107.

FIG. 3 illustrates an example of three STAs 106, 107, and 109communicating with AP 108 over the base-channel and STA 106communicating with STAs 107 and 109 via two TDLS direct links over theoff-channel using the RSDB configuration in accordance with oneembodiment of the present disclosure. STAs 106, 107, and 109 may allsupport RSDB and TDLS over the 5 GHz off-channel. STA 106 as theinitiator may establish a TDLS direct link with STA 107 and a TDLSdirect link with STA 109 in the manner described in FIG. 2. STA 106 maymaintain a list of peer STAs indicating that STAs 107 and 109 have TDLSdirect links.

STA 106 may simultaneously communicate with STA 107 or STA 109 overtheir respective off-channel TDLS direct link and with AP 108 and legacySTAs over the base-channel in the RSDB configuration. STAs 107 or 109may simultaneously communicate with STA 106 over its respectiveoff-channel TDLS direct link and with AP 108 over the base-channel inthe RSDB configuration. STA 106 as the initiator may manage thebandwidth and the medium of the 5 GHz off-channel when communicatingwith both STA 107 and 109. For example, STA 106 may arbitrate betweenrequests for access to the 5 GHz off-channel to prioritize or allocatechannels in the 5 GHz band between TDLS direct links to STAs 107 and109. In one embodiment, multiplexed access to the communicationresources between the two off-channel TDLS direct links may beimplemented using time-division multiple access (TDMA),frequency-division multiple access (FDMA), code-division multiple access(CDMA) techniques, or a combination thereof.

FIG. 4 shows a flow chart of a method 400 for an initiator STA toestablish a connection with an AP over the base-channel forcommunicating with the AP and legacy STAs and to establish a TDLS directlink with a peer STA over the off-channel in the RSDB configuration inaccordance with one embodiment of the present disclosure. The method ofFIG. 4 may be practiced by the STAs 106, 107, or 109 of FIGS. 1, 2 and 3in a WLAN network that includes the AP 108 in a BSS that complies withthe WiFi standard. The initiator STA and the peer STA are dual-bandcapable STAs that support 2.4 GHz/5 GHz RSDB with TDLS direct linkcapability.

At operation 401, the initiator STA connects to the AP in the 2.4 GHzbase-channels. The initiator STA may discover and associate with the APover the base-channel to establish a link with the AP. Once associatedwith the AP, the initiator STA may receive beacons or commands from theAP over the base-channel. The initiator STA may also transfer data withone or more peer STAs of the BSS over the base-channel or to devices ofa wide area network via the AP link and a gateway. The peer STAs arealso connected to the AP through their respective 2.4 GHz base-channelAP links.

At operation 403, the initiator STA establishes a TDLS link with a peerSTA over the base-channel. The initiator STA may transmit a TDLS setuprequest frame via the AP over the base-channel to advertise itsoff-channel capability to the peer STAs of the BSS and to inquire aboutthe off-channel capabilities of the peer STAs. If a peer STA isdual-band capable and supports TDLS direct links, the peer STA mayrespond with a TDLS response frame back to the initiator STA 106indicating that the peer STA supports TDLS off-channel capability. Theinitiator STA may then establish a TDLS link with the peer STA initiallyover the base-channel. The TDLS response frame may also contain a TDLSchannel switching capability field that indicates whether the peer STAis capable of RSDB operation using the off-channel TDLS link.

At operation 405, the initiator STA checks the TDLS channel switchingcapability field of the TDLS response frame from the peer STA todetermine if the peer STA supports RSDB operation using the off-channelTDLS link. If the peer STA does not support RSDB operation using theoff-channel TDLS link, for example if the peer STA has only one MAC andPHY transceiver that may be configured to operate over either thebase-channel or the off-channel, but not both channels simultaneously,the initiator STA and the peer STA may establish their TDLS direct linkin the virtual simultaneous dual band (VSDB) configuration at operation407. In the VSDB configuration, the initiator STA toggles betweenoperating in the off-channel to service the TDLS direct link with thepeer STA and operating in the on-channel to receive beacons andcommunicate with legacy STAs via the AP.

At operation 409, if the peer STA supports RSDB operation using theoff-channel TDLS link, for example if the peer STA has two pairs of MACand PHY that may be configured to operate both the base-channel and theoff-channel simultaneously, the initiator STA initiates a channel switchrequest for the 5 GHz off-channel. The initiator STA may transmit a TDLSchannel switch request frame over the TDLS direct link in the basechannel to the peer STA. The peer STA may respond with a TDLS channelswitch response frame over the TDLS direct link in the base channel tothe initiator STA.

At operation 411, upon successful channel switch negotiation, theinitiator STA switches the TDLS direct link with the peer STA from thebase-channel to the off-channel. The initiator STA may then listen fortransmission from the peer STA.

At operation 413, the initiator receives beacons and communicates withthe AP and with legacy STAs over the base-channel and communicates withthe peer STA over the off-channel in the RSDB configuration. Theinitiator STA may operate the base-channel and the off-channelsimultaneously. Therefore, in contrast to the VSDB configuration, theinitiator STA does not switch between the base-channel and theoff-channel when the initiator STA transfers data with the legacy STAsover the base-channel and with the peer STA over the off-channel. Bothlinks may be fully maintained without incurring the performancepenalties of increased latency and reduced throughput when the initiatorSTA has to put one link to the power saving mode when serving the otherlink.

FIG. 5 is a block diagram of a dual-band radio device of a STA thatsupports RSDB communication over the base-channel with an AP and overthe off-channel with peer STAs using TDLS direct links in accordancewith one embodiment of the present disclosure. The dual-band radiodevice 205 includes a first pair of MAC 311 and PHY wireless core 321configured to implement a 2.4 GHz base-channel link with the AP toreceive beacons and to communicate with the AP, as well as to transferdata with legacy STAs that operate in the 2.4 GHz band via the AP. Asecond pair of MAC 310 and PHY wireless core 320 is configured toimplement one or more 5 GHz off-channel TDLS links to transfer data withone or more peer STAs.

In one embodiment, the first pair of MAC module 311 and PHY wirelesscore 321 may only support the 2.4 GHz band. The first pair of MAC module311 and PHY wireless core 321 may be configured to transmit and receiveusing antenna 150 (1). The second pair of MAC module 310 and PHYwireless core 320 may be capable of supporting both the 2.4 GHz and the5 GHz bands but is configured for the 5 GHz operation for the TDLSdirect links. The second pair of MAC module 310 and PHY wireless core320 may be configured to transmit and receive using antenna 150 (2). Inone embodiment, antennas 150(1) and 150(2) may each be an array ofantennas that may be configured as MIMO antennas.

MAC modules 310 and 311 encapsulate data into frames to be transmittedwirelessly, then forward the frames to PHY wireless cores 320 and 321 tobe modulated and up-converted into radio frequency (RF) signals in the 5GHz and 2.4 GHz bands and transmitted via antennas 150(2) and 150(1),respectively. PHY wireless cores 320 and 321 also receive RF signals inthe 5 GHz and 2.4 GHz bands from antennas 150(2) and 150(1) to bedown-converted and demodulated into frames of received data processed byMAC modules 310 and 311, respectively. In one embodiment, each of thePHY wireless cores 320 and 321 includes radio transceiver circuitry,modulator and demodulator (modem) circuitry, and other physical layercircuit modules for performing the wireless transmission and reception.

In the dual-band radio device 205, MAC module 310 for the 5 GHz band mayfunction as a master or primary “slice,” while MAC 311 for the 2.4 GHzband may function as a slave or secondary “slice.” MAC module 310 forthe master slice is interconnected to a processing unit 201, such asinterconnected over AXI to a single ARM core. The processing unit 201may implement the method of FIG. 4 to establish a link over the 2.4 GHzbase-channel for communicating with an AP and to establish a TDLS directlink over the 5 GHz off-channel to communicate with the dual-band radiodevice of a peer STA in the RSDB configuration. Data provided from theprocessing unit 201 to the MAC module 311 of the slave slice is passedto the slave slice by the MAC module 310 of the master slice.

FIG. 6 is a block diagram of a dual-band WLAN device 600 of a STA thatsupports RSDB communication over the base-channel with an AP and overthe off-channel with peer STAs using TDLS direct links in accordancewith one embodiment of the present disclosure. The dual-band WLAN device600 includes two independent cores that provide concurrent 802.11operation in both 2.4 GHz and 5 GHz bands. A primary core includes the802.11 MAC 602 and 802.11 PHY 604 that may operate at the off-channel 5GHz band at 20, 40, or 80 MHz channels in 2×2 MIMO mode to provide anoff-channel TDLS link to transfer data with a dual-band WLAN device of apeer STA. An auxiliary core includes the 802.11 MAC 606 and 802.11 PHY608 that may operate at the base-channel 2.4 GHz band at 20 MHz channelsin 2×2 MIMO mode to provide a base-channel link with an AP tocommunicate with the AP and to transfer data with legacy STAs thatoperate in the 2.4 GHz band. The primary core and auxiliary cores may beconfigured to support two fully simultaneous MIMO channels in RSDBoperation.

The dual-band WLAN device 600 includes dual-band RF transceivers orradios 610 and 612. The dual-band RF transceivers 610/612 includefilters, power amplifiers, mixers, gain-control function, etc., thatmodulate and up-convert the baseband signals from the 802.11 PHY to the2.4 GHz and 5 GHz bands, and filter and down-convert the 2.4 GHz and 5GHz RF signals to baseband. The transceivers 610/612 may interface withan external RF front end device 614 that provides low-noise amplifiers,power amplifiers, and switches for additional signal conditioning in the2.4 GHz and 5 GHz bands. The dual-band transceivers 610/612 or externalRF front end device 614 may transmit and receive through one or moreantennas 618. The dual-band WLAN device 600 may interface to a hostprocessor through a PCI Express bus 616. The WLAN operation may becompatible with the various 802.11x standards, including 802.11z thatprovides the facility for dual-band capable WLAN devices of peer STAs toestablish TDLS direct links with other in the 5 GHz band.

In one embodiment, the dual-band WLAN device 600 may include a memoryand a processing device (not shown). The memory may be synchronousdynamic random access memory (DRAM), read-only memory (ROM)), or othertypes of memory, which may be configured to store the code to performthe function of a WLAN driver. The processing device may be provided byone or more general-purpose processing devices such as a microprocessor,central processing unit, or the like. In an illustrative example,processing device may comprise a complex instruction set computing(CISC) microprocessor, reduced instruction set computing (RISC)microprocessor, very long instruction word (VLIW) microprocessor, or aprocessor implementing other instruction sets or processors implementinga combination of instruction sets. Processing device may also compriseone or more special-purpose processing devices such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), a digital signal processor (DSP), network processor, or thelike. The processing device may be configured to execute the operationsdescribed herein, in accordance with one or more aspects of the presentdisclosure, to establish a link over the 2.4 GHz base-channel forcommunicating with an AP and a TDLS direct link over the 5 GHzoff-channel for communicating with a peer STA in the RSDB configurationdiscussed herein.

Unless specifically stated otherwise, terms such as “receiving,”“generating,” “verifying,” “performing,” “correcting,” “identifying,” orthe like, refer to actions and processes performed or implemented bycomputing devices that manipulates and transforms data represented asphysical (electronic) quantities within the computing device's registersand memories into other data similarly represented as physicalquantities within the computing device memories or registers or othersuch information storage, transmission or display devices.

Examples described herein also relate to an apparatus for performing theoperations described herein. This apparatus may be specially constructedfor the required purposes, or it may comprise a general purposecomputing device selectively programmed by a computer program stored inthe computing device. Such a computer program may be stored in acomputer-readable non-transitory storage medium.

Certain embodiments may be implemented as a computer program productthat may include instructions stored on a machine-readable medium. Theseinstructions may be used to program a general-purpose or special-purposeprocessor to perform the described operations. A machine-readable mediumincludes any mechanism for storing or transmitting information in a form(e.g., software, processing application) readable by a machine (e.g., acomputer). The machine-readable medium may include, but is not limitedto, magnetic storage medium (e.g., floppy diskette); optical storagemedium (e.g., CD-ROM); magneto-optical storage medium; read-only memory(ROM); random-access memory (RAM); erasable programmable memory (e.g.,EPROM and EEPROM); flash memory; or another type of medium suitable forstoring electronic instructions. The machine-readable medium may bereferred to as a non-transitory machine-readable medium.

The methods and illustrative examples described herein are notinherently related to any particular computer or other apparatus.Various general purpose systems may be used in accordance with theteachings described herein, or it may prove convenient to construct morespecialized apparatus to perform the required method steps. The requiredstructure for a variety of these systems will appear as set forth in thedescription above.

The above description is intended to be illustrative, and notrestrictive. Although the present disclosure has been described withreferences to specific illustrative examples, it will be recognized thatthe present disclosure is not limited to the examples described. Thescope of the disclosure should be determined with reference to thefollowing claims, along with the full scope of equivalents to which theclaims are entitled.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”,“comprising”, “includes”, and/or “including”, when used herein, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. Also, the terms “first,” “second,”“third,” “fourth,” etc., as used herein are meant as labels todistinguish among different elements and may not necessarily have anordinal meaning according to their numerical designation. Therefore, theterminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Although the method operations were described in a specific order, itshould be understood that other operations may be performed in betweendescribed operations, described operations may be adjusted so that theyoccur at slightly different times or the described operations may bedistributed in a system which allows the occurrence of the processingoperations at various intervals associated with the processing.

Various units, circuits, or other components may be described or claimedas “configured to” or “configurable to” perform a task or tasks. In suchcontexts, the phrase “configured to” or “configurable to” is used toconnote structure by indicating that the units/circuits/componentsinclude structure (e.g., circuitry) that performs the task or tasksduring operation. As such, the unit/circuit/component can be said to beconfigured to perform the task, or configurable to perform the task,even when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” or “configurable to” language include hardware—forexample, circuits, memory storing program instructions executable toimplement the operation, etc. Reciting that a unit/circuit/component is“configured to” perform one or more tasks, or is “configurable to”perform one or more tasks, is expressly intended not to invoke 35 U.S.C.112, sixth paragraph, for that unit/circuit/component. Additionally,“configured to” or “configurable to” can include generic structure(e.g., generic circuitry) that is manipulated by software and/orfirmware (e.g., an FPGA or a general-purpose processor executingsoftware) to operate in manner that is capable of performing the task(s)at issue. “Configured to” may also include adapting a manufacturingprocess (e.g., a semiconductor fabrication facility) to fabricatedevices (e.g., integrated circuits) that are adapted to implement orperform one or more tasks. “Configurable to” is expressly intended notto apply to blank media, an unprogrammed processor or unprogrammedgeneric computer, or an unprogrammed programmable logic device,programmable gate array, or other unprogrammed device, unlessaccompanied by programmed media that confers the ability to theunprogrammed device to be configured to perform the disclosedfunction(s).

The foregoing description, for the purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. For example, theTDLS with RSDB configuration may be extended to support differentchannels of a frequency band, not just multiple frequency bands. Manymodifications and variations are possible in view of the aboveteachings. The embodiments were chosen and described in order to bestexplain the principles of the embodiments and its practicalapplications, to thereby enable others skilled in the art to bestutilize the embodiments and various modifications as may be suited tothe particular use contemplated. Accordingly, the present embodimentsare to be considered as illustrative and not restrictive, and theinvention is not to be limited to the details given herein, but may bemodified within the scope and equivalents of the appended claims.

What is claimed is: 1-20. (canceled)
 21. A dual-band wireless device,comprising: a memory including instructions; and a processor configuredexecute the instructions to: establish a first wireless link with anaccess point (AP) using a first frequency band; establish a tunneleddirect link setup (TDLS) link with a peer wireless device using thefirst frequency band; switch from using the first frequency band for theTDLS link with the peer wireless device to using a second frequency bandfor the TDLS link with the peer wireless device; and using a real-timesimultaneous dual band (RSDB) configuration to concurrently communicatewith the AP through the first wireless link using the first frequencyband and with the peer wireless device through the TDLS link using thesecond frequency band.
 22. The dual-band wireless device of claim 21,wherein the first frequency band is at 2.4 GHz and the second frequencyband is at 5 GHz.
 23. The dual-band wireless device of claim 21, whereinthe dual-band wireless device comprises: a first pair of a media accesscontroller (MAC) module and a physical layer (PHY) core configured toprocess data to be transmitted or data received using the firstfrequency band; and a second pair of a MAC module and a PHY coreconfigured to process data to be transmitted or data received using thesecond frequency band, wherein the first pair of the MAC module and thePHY core operate concurrently with the second pair of the MAC module andthe PHY core during operation of the RSDB configuration.
 24. Thedual-band wireless device of claim 21, wherein to establish the TDLSlink with the peer wireless device using the first frequency band, theprocessor is configured execute the instructions to: transmit a TDLSsetup request frame on the first wireless link to the peer wirelessdevice; and receive a TDLS setup response frame on the first wirelesslink from the peer wireless device.
 25. The dual-band wireless device ofclaim 24, wherein the switch is responsive to a determination that thepeer wireless device supports the RSDB configuration using the secondfrequency band, wherein the determination is based on an indication inthe TDLS setup response frame of a TDLS capability of the peer wirelessdevice.
 26. The dual-band wireless device of claim 21, wherein to switchthe TDLS link from the first frequency band to the second frequencyband, the processor is configured to execute the instructions to:transmit a channel switch request frame to the peer wireless device overthe TDLS link using the first frequency band to the peer wirelessdevice; and receive an acknowledgement frame over the TDLS link usingthe first frequency band from the peer wireless device.
 27. Thedual-band wireless device of claim 21, wherein the processor is furtherconfigured to execute the instructions to toggle between using the firstfrequency band and using the second frequency band to allow thedual-band wireless device to communicate with the AP through the firstwireless link and with the peer wireless device through the TDLS link ina virtual simultaneous dual band (VSDB) configuration.
 28. The dual-bandwireless device of claim 21, wherein the processor is further configuredto execute the instructions to disable the TDLS link on the secondfrequency band.
 29. The dual-band wireless device of claim 21, whereinthe processor is further configured to execute the instructions to:establish a second TDLS link with a second peer wireless device, usingthe second frequency band; and use the RSDB configuration toconcurrently communicate with the AP using the first frequency band andcommunicate with the second peer wireless device through the second TDLSlink using the second frequency band.
 30. The dual-band wireless deviceof claim 29, wherein the processor is further configured to execute theinstructions to arbitrate between channels of the second frequency bandto communicate with the peer wireless device over the TDLS link on thesecond frequency band or with the second peer wireless device over thesecond TDLS link on the second frequency band.
 31. A non-transitorymachine-readable medium including instructions that when executed by oneor more processors, perform operations comprising: establishing a firstwireless link with an access point (AP) via a first frequency band;establishing a tunneled direct link setup (TDLS) link with a peerwireless device using the first frequency band; switching from using thefirst frequency band for the TDLS link to using a second frequency bandfor the TDLS link; and using a real-time simultaneous dual band (RSDB)configuration, communicating with the peer wireless device through theTDLS link using the second frequency band and concurrently communicatingwith the AP through the first wireless link using the first frequencyband.
 32. The non-transitory machine-readable medium of claim 31,wherein the first frequency band is at 2.4 GHz and the second frequencyband is at 5 GHz.
 33. The non-transitory machine-readable medium ofclaim 31, wherein establishing the TDLS link with the peer wirelessdevice using the first frequency band comprises: transmitting a TDLSsetup request frame on the first wireless link to the peer wirelessdevice; and receiving a TDLS setup response frame on the first wirelesslink from the peer wireless device.
 34. The non-transitorymachine-readable medium of claim 33, further comprising determining thatthe peer wireless device supports the RSDB configuration on the secondfrequency band by determining from the TDLS setup response frame, a TDLScapability of the peer wireless device.
 35. The non-transitorymachine-readable medium of claim 31, wherein the switching of the TDLSlink from the first frequency band to the second frequency bandcomprises: transmitting a channel switch request frame to the peerwireless device over the TDLS link on the first frequency band to thepeer wireless device; and receiving an acknowledgement frame over theTDLS link on the first frequency band from the peer wireless device. 36.The non-transitory machine-readable medium of claim 31, furthercomprising toggling between using the first frequency band and thesecond frequency band to communicate with the AP through the firstwireless link and with the peer wireless device through the TDLS link ina virtual simultaneous dual band (VSDB) configuration.
 37. Thenon-transitory machine-readable medium of claim 31, further comprising:establishing a second TDLS link with a second peer wireless device usingthe second frequency band; and using the RSDB configuration,communicating with the second peer wireless device through the secondTDLS link using the second frequency band while communicating with theAP through the first wireless link using the first frequency band. 38.The non-transitory machine-readable medium of claim 37, furthercomprising arbitrating between channels of the second frequency band tocommunicate with the peer wireless device over the TDLS link on thesecond frequency band or with the second peer wireless device over thesecond TDLS link on the second frequency band.
 39. A system comprising:a plurality of antennas; a dual-band communication device configured tocouple to the antennas to cause the plurality of antennas to transmit orreceive over a plurality of frequency bands; and a processing deviceconfigured to: establish, through the dual-band communication device andthe plurality of antennas, a first wireless link on the first frequencyband to a first wireless device; establish, through the dual-bandcommunication device and the plurality of antennas, a tunneled directlink setup (TDLS) link on the first frequency band to a second wirelessdevice; switch from using the first frequency band for the TDLS linkwith the second wireless device to using a second frequency band for theTDLS link with the second wireless device; and use a real-timesimultaneous dual band (RSDB) configuration to communicate with thesecond wireless device through the TDLS link using the second frequencyband and in parallel communicate with the first wireless device throughthe first wireless link using the first frequency band.
 40. The systemof claim 39, wherein the switch is responsive to a determination thatthe second wireless device supports the RSDB configuration using thesecond frequency band.